Classic psychedelics carry minimal medical risks such as toxicity and overdose, and many persistent negative perceptions of psychological risks—including abuse liability and dependence—are unsupported by current scientific evidence when use occurs in regulated or medical contexts. Most reported adverse effects are not observed under these conditions. The review underscores the need for clinicians and therapists to maintain high safety and ethical standards and for balanced media reporting to avoid future controversies and allow continued research.
Sub-chronic exposure to the NMDA receptor antagonist phencyclidine (PCP) in rats produced localized reductions in grey matter density in the hippocampus, anterior cingulate cortex, ventral striatum, and amygdala, along with reduced cortical thickness in the insular cortex. PCP-treated rats also showed impaired sustained visual attention on a 5-choice serial reaction time task, especially under higher attentional load, but no significant effect on attentional filtering in an acoustic startle paradigm. These findings indicate that NMDA receptor antagonism can cause brain structural abnormalities in regions implicated in schizophrenia and dissociable attentional deficits.